tfarny
Poster Extraordinaire
It's really easy to get something close enough for rock n roll. But if you really want an acoustic to sound on stage like it does in your living room, especially at drummer / bass player volumes, it does get tricky..
When I was looking to mod my acoustic for an amplifier .. there were the lick 'n stick style pad piezo pickups that go under the sound board and the under saddle ribbon/wire style that required shaving down your bridge. I'd used one of those wire styles under a Tele bridge of a project guitar to get acoustic tones so I knew they worked. They could be had for five or ten dollars back then but needed some sort of pre-amp that was five dollars and a five dollar battery and then the acoustic guitar style amp.
I'm all electric guitar and just have the acoustic for banging around on so I ended up making a strip of wood that fit behind the sound hole to suspend a regular Strat single coil as close to the neck as possible then ran that direct to a strap-pin jack. I only need one guitar amp for both electric and 'acoustic' guitars. If I want to sound more like an acoustic guitar I twist knobs on pedals and amp, otherwise it sounds more like a Strat -- which was one of those items that taught me there is no such thing as 'tone wood'.
I'd say to just get a lick 'n stick pad pickup for the electric guitar, a five dollar pre-amp, and spend your money on your acoustic amp rather than trying to spread the budget equally around all the little bits.
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